Latch/unlatch mechanism for cassette holder door

ABSTRACT

A latch/unlatch mechanism particularly useful for a cassette door holder having a latch hook thereon. The latch mechanism comprises a solenoid including a plunger and a resilient onepiece spring latch arm formed of a strip of resilient material and operatively connected to the solenoid plunger. When the solenoid is unenergized, the latch arm is engageable with the latch hook on the cassette door and manually locked by overcoming the resiliency of the spring material and yieldingly interlocking with the latch hook. When the solenoid is energized, the actuated plunger overcomes the resiliency of the spring material, disengaging the latch arm from the latch hook to enable the cassette door to be opened, and upon de-energization of the solenoid, the latch arm will return the plunger to its original position. The mechanism is also provided with a retention member which engages and constrains the plunger stroke during the restoration of the plunger to its extended position upon deenergization of the solenoid. This mechanism eliminates the need for a latch pawl, a pivot and associated parts as well as a solenoid plunger return spring.

United States Patent [191 Shiurila John Shiurila, Alameda, Calif.

[73] Assignee: The Singer Company, New York,

[22] Filed: Sept. 17, 1973 [21] Appl. No.: 398,275

[75] Inventor:

[52] US. Cl 292/81, 292/201 [51] Int. Cl. E05c 19/06 [58] Field of Search 70/282; 292/80, 81, 86, 292/96, 144, 201, 341.16; 335/253, 254

[56] References Cited UNITED STATES PATENTS 684,018 10/1901 Wellman 292/86 742,563 10/1903 Beehler 292/86 1,769,539 7/l930 O'Keeffe t 335/253 2,034,971 3/1936 Brockway 292/96 X 2,395,164 2/1946 Cole l 335/254 X 2,543,214 2/1951 Wildberg 292/201 Primary Examiner-Roy D. Frazier Assistant ExaminerWilliam E. Lyddane Attorney, Agent, or FirmEdward L. Bell; Joseph R. Dwyer [451 Nov. 19, 1974 57 ABSTRACT A latch/unlatch mechanism particularly useful for a cassette door holder having a latch hook thereon. The latch mechanism comprises a solenoid including a plunger and a resilient one-piece spring latch arm formedv of a strip of resilient material and operatively connected to the solenoid plunger. When the solenoid is unenergized, the latch arm is engageable with the latch hook on the cassette door and manually locked by overcoming the resiliency of the spring material and yieldingly interlocking with the latch hook. When the solenoid is energized, the actuated plunger overcomes the resiliency of the spring material, disengaging the latch arm from the latch hook to enable the cassette door to be opened, and upon de-energization of the solenoid, the latch arm will return the plunger to its original position. The mechanism is also provided with a retention member which engages and constrains the plunger stroke during the restoration of the plunger to its extended position upon deenergization of the solenoid. This mechanism eliminates the need for a latch pawl, a pivot and associated parts as well as a solenoid plunger return spring.

4 Claims, 4 Drawing Figures BACKGROUND OF THE INVENTION BRIEF DESCRIPTION OF THE PREFERRED EMBODIMENT Turning now to the drawings, it can be seen that the In cassette players and recorders there has been a 5 latch/unlatch mechanism constructed in accordance need and an ever-increasing demand for a more compact, more reliable, door latch, yet which is as inexpensive as possible. Heretofore, in order to keep costs down, the latch for a cassette player or recorder was usually a mechanically operable spring-type latch. Sometimes, however, if an electrically operated latch was desired, a solenoid type was selected. But the conventional solenoid-operated door latch required a latch pawl, its pivot and associated parts, plus a plunger return spring, all of which contributed to the cost of the latch mechanisms, making them non-competitive in the market place, and for that reason, were seldom selected to be used.

The present invention, as will be evident, provides an economical, feasible, door latch mechanism that is price-competitive and thus suitable for cassette players and recorders and, of course, can be used anywhere a door latch of this type is required or desired.

SUMMARY OF THE INVENTION This invention comprises a latch/unlatch mechanism having a solenoid, including a plunger, which actuates a spring lever arm having an extremity which operates to spring-latch the hook on the door of the cassette holder. In its locking position, with the solenoid deenergized, the spring lever is such that it will springlatch the hook of the cassette door when the door is closed manually; the hook on the cassette door overcoming the resiliency of the spring to permit the end of the spring latch arm to engage with the door hook. The spring lever arm is, however, operably attached to the solenoid plunger so that energization of the solenoid coil causes the plunger to pull back the spring lever arm against the resiliency of the spring from the door hook and thus unlatch the door. Upon deenergization of the solenoid, the spring action of the lever arm returns the plunger to its original extended position, thus eliminating the need for conventional return springs normally found on present solenoid-actuated devices. The spring lever arm isalso provided with a retention tab formed of a part of the spring lever arm for limiting the travel of the plunger within its required stroke.

This latch/unlatch mechanism provides a simple economic device for locking of a door which may be unlocked by electrical solenoid action and will restore itself to normal position upon de-energization of the solenoid. The position and travel of the solenoid plunger is such that it is always in optimum magnetic position with respect to the coil without additional return springs, pawls, etc., since the latch arm itself is the return spring for the plunger as well as the latch.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an elevation view illustrating the unlatching action upon energization of the solenoid;

with the teachingsof this invention is indicated in its entirety as 10 and shown engageable with a hook 12 on a holder door 14 of a cassette deck which may be a recorder or player or both.

The latch/unlatch mechanism 10 comprises a solenoid 16 having a coil 18 and an actuatable plunger 20 shown engageable with the spring lever, indicated in its entirety as 22, and which comprises the spring lever arm 24 formed with a hook 26 which, in the embodiment shown, is a piece of the spring sheet or strip material bent back on itself.

At the other extremity of the spring lever arm 24 there is a bend 28 formed in the material so that the arm itself is normal to the orientation of the plunger or I or 2 beyond in the direction of the hook I2 and the material is also formed to engage a base 30 on which the solenoid 16 is mounted.

The spring lever arm 24 is provided with a keyhole slot 32 for the insertion of the head 34 of the plunger 20, which head is formed by the reduced portion defm ing an annular groove 36 in the outer extremity of the plunger. One wall 38 of the groove 36 provides an engagement abutment for the spring lever arm 24, and, as can be seen in the drawings, being resilient, will serve to pull the plunger to its extended position relative to i the coil 18, which position is to the right, as shownin the drawings. The other wall 40 of the annular groove 36 provides an engagement abutment for a retention tab 42 which is formed out of the spring arm 24 by being cut centrally but longitudinally of the strip material beginning at the keyhole slot 30 so that the retention tab is an integral part of the spring lever arm to give resilency to the retention tab. This retention tab, in engagement with the other wall or abutment 40 of the annular groove 36, while not affecting retraction of the plunger serves to limit the travel of the plunger within its required stroke during the restoring of the plunger to its extended position upon de-energization of the solenoid. The space between the retention tab and the arm 24 is determined by the gap formed by the groove 36.

From the foregoing it can be seen that the cassette door may manually be closed and latched by the pushing of the door so that the hook l2 overcomes the resiliency of the lever 24 permitting its hook 26 to engage the hook 12. Upon energization of the solenoid, the plunger 20 is pulled to the left as shown in the drawings so that the hook 26 disengages the hook 12 by overcoming the resiliency of the arm 24.

Upon de-energization of the solenoid, the resiliency of the spring lever arm 24 will move the plunger to its extended position, which is to the right such as shown in FIG. 2. With this arrangement there is no requirement for latch pawl, the latch pawl pivot and all associated parts, as well as eliminates the solenoid plunger return spring normally found in latch mechanisms of this type.

It is to be noted that the lever arm 24 remains relatively straight with most of the resiliency being overcome by the plunger at the bend 28.

What is claimed is:

l. A latch/unlatch mechanism particularly useful for a cassette holder door comprising:

a solenoid including a coil and plunger means responsive to the magnetic field in the coil; resilient latch means yieldably engageable with a hook on said door and operatively and directly attached to said plunger means and disengageable from said hook by the bending thereof upon energization of said solenoidand the retraction of said plunger means; and tab means integral with said resilient latch means and operatively engaged with said plunger means for limiting the overtravel of said plunger means beyond the required stroke upon de-energization of said coil. 2. The mechanism as claimed in claim 1 wherein said latch means has an aperture and wherein said plunger means has an annular groove which engages said aperture for operative retention therein.

3. The mechanism claimed in claim.2 wherein said annular groove forms two abutment surfaces and is adjacentthe outer end thereof and wherein the first abutment surface thereof engages the latch means and wherein the second abutment surface engages the tab means which acts as a restraint against the outward movement of the plunger means.

4. The mechanism as claimed in claim 1 wherein said latch means comprises an arm of resilient material provided with a hook which engages the hook of the door and which is movable upon energization of the solenoid so as to disengage the hook on said door and wherein said tab means is formed by an intermediate finger integral with the arm and engageable with the plunger means. 

1. A latch/unlatch mechanism particularly useful for a cassette holder door comprising: a solenoid including a coil and plunger means responsive to the magnetic field in the coil; resilient latch means yieldably engageable with a hook on said door and operatively and directly attached to said plunger means and disengageable from said hook by the bending thereof upon energization of said solenoid and the retraction of said plunger means; and tab means integral with said resilient latch means and operatively engaged with said plunger means for limiting the overtravel of said plunger means beyond the required stroke upon de-energization of said coil.
 2. The mechanism as claimed in claim 1 wherein said latch means has an aperture and wherein said plunger means has an annular groove which engages said aperture for operative retention therein.
 3. The mechanism claimed in claim 2 wherein said annular groove forms two abutment surfaces and is adjacent the outer end thereof and wherein the first abutment surface thereof engages the latch means and wherein the second abutment surface engages the tab means which acts as a restraint against the outward movement of the plunger means.
 4. The mechanism as claimed in claim 1 wherein said latch means comprises an arm of resilient material provided with a hook which engages the hook of the door and which is movable upon energization of the solenoid so as to disengage the hook on said door and wherein said tab means is formed by an intermediate finger integral with the arm and engageable with the plunger means. 